The first time you hit a page after the upgrade you'll find a delay as WP Satistics processes the database changes, if you wait a bit the page should render when that completes. Otherwise, reloading the page should also work fine.

I had the same problem.... repeated refreshes, no errors in PHP logs, admin page was blank (2 - 3 mins wait, followed by refreshes) and post-content screens stopped content display at point the widget was executed.

I manually disable the plugin by renaming the directory to verify the issue, then restored the name ... and the problem seems to have gone away. The widget runs as expected, the admin panel is back and all seems well.

On a second look, the errors I have in my log are not from this plugin, they just happened around the same time. Sorry about that.

However, I have still not found a resolution. I tried renaming the directory and then installing the plugin fresh, but that did not work.

I checked a 3rd site I run that uses this plugin, which I have not updated yet, and it is running 6.1. I usually updated all my sites around the same time, so on the two sites I am having an issue with, would most likely have gone from version 6.1 to 7.0.1